Originally Posted by rhouck
You probably won't need an external GPS, especially if you have a newer Android phone. I would try without one.
OBD -- check Amazon for "ELM 327" bluetooth units. You should be able to get one for <$20. If I remember correctly, you want one that is version 1.4 or newer, but you might want to double-check that (been awhile since I bought one). I would buy from Amazon and worst case, if it doesn't work, return it. Though I had no problems with mine and I just picked a random one from Amazon
Problem is that if you use an Iphone it needs to be a WIFI OBD reader. Usually those are 75+. I went with Kiwi since it was available at Fry's, much easier to return.
Bluetooth works for Android phones.